کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4727929 | 1356405 | 2009 | 22 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Petrological evolution of silica-undersaturated sapphirine-bearing granulite in the Paleoproterozoic Salvador-Curaçá Belt, Bahia, Brazil
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
زمین شناسی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The Salvador-Curaçá Belt, located in São Francisco Craton, Brazil, was subjected to granulite facies metamorphism during the Paleoproterozoic orogeny (c. 2.0 Ga). Well preserved in enclaves of silica-undersaturated sapphirine-bearing granulite occur in a charnockite outcrop located along a kilometric-scale shear zone. The sapphirine-bearing granulite preserves domains with distinct mineral assemblages that record interactions between melt and peritectic phases (orthopyroxene1 + spinel1 + biotite1). Sapphirine was crystallized in the Si-poor cores of the enclaves, sillimanite and spinel-cordierite symplectites in the intermediate Si-rich domains between cores and margins, and garnet and quartz-bearing cordierite/biotite symplectites in Si-rich margins of the enclaves. Melt-rock interactions and metamorphism occurred at ultrahigh temperatures of 900-950 °C at 7.0-8.0 kbar pressures. The mineralogical evolution of the domains reflects not only the influence of changes in bulk composition in the equilibrium volume of the reactions but also P-T changes during orogeny evolution. Electron microprobe dating of monazite both in the sapphirine-bearing granulite and charnockite indicates UHT metamorphism timing at c. 2.08-2.05 Ga that is related to global Paleoproterozoic UHT metamorphic events that occurred during the Columbia supercontinent assembly.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Gondwana Research - Volume 15, Issue 1, February 2009, Pages 49-70
Journal: Gondwana Research - Volume 15, Issue 1, February 2009, Pages 49-70
نویسندگان
C. de M.M. Leite, J.S.F. Barbosa, P. Goncalves, C. Nicollet, P. Sabaté,